It is often desirable to provide cut sheets to a printer or other web or sheet utilization device from a high volume source such as a roll. Most utilization devices are not adapted to receive an uncut continuous web. Rather, utilization devices typically require a stack of cut sheets to be positioned at a feed location in which the sheets are deshingled and routed through the utilization device as needed.
Applicants related U.S. Pat. No. 5,130,724 and co-pending continuation-in-part application Ser. No. 07/773,887 each disclose systems for directly feeding sheets to utilization devices adapted for normally accepting stacks of cut sheets. The directly fed sheets can be derived from rolls of continuous web that are separated by an external cutter. According to this invention, sheets are delivered (replenished) on demand to the stack feed location of the utilization device as sheets are drawn from the stack by the utilization device. The disclosures of U.S. patent application Ser. No. 07/773,887 and U.S. Pat. No. 5,130,724 are hereby expressly incorporated herein by reference.
The method and apparatus disclosed by each of the prior related applications relate essentially to the provision of sheets to a utilization device not normally adapted for receiving a direct stream of sheets derived, typically, from a continuous web. Hence, the teachings of these applications are directed largely toward the delivery of sheets at selected times to the utilization device stack feed location without direct interconnection or communication between the utilization device and the external feeder and cutter. As high volume web handling and production versatility become more important, utilization devices are now beginning to incorporate specific ports and communication linkages to enable interactive coupling between an external feed unit and the utilization device. One particular utilization device, the Xerox 4135 series laser printer, is so adapted to enable interactive interface with an external feed unit.
In view of the above-described prior art, it is an object of this invention to provide an external high speed sheet feeder unit with a capability of directly interfacing with a utilization device having a port for receiving sheets. It is another object of this invention to provide a sheet feeder having a configuration that does not interfere with normal functioning of the utilization device and that allows further expansion of the utilization device via other ports.